Which statement best describes vortex generators?

• A. It reduces fuel consumption by reducing drag.
• B. It delays boundary layer separation.
• C. It creates lift on the wing.
• D. It heats the wing surface.

Answer: (B)

Vortex generators are small flow-control devices that create orderly vortices on the wing surface to energize the boundary layer. By bringing higher-energy air from above the boundary layer into the layer right near the surface, they help keep the airflow attached to the surface longer, especially at high angles of attack or when flaps are extended. This delay in flow separation helps maintain lift and control effectiveness and reduces buffet, which is why they’re used to improve stall characteristics and handling.

They don’t generate lift directly themselves, and they aren’t primarily a heat source or a fuel-saving device. They can add some drag due to the disturbed flow, so their main purpose isn’t to reduce drag but to prevent premature separation. That’s why delaying boundary layer separation is the best description of their function.